Tubing anchor



J. D. NIXON TUBING ANCHOR March 27, 1951 2 Sheets-Sheet 1 Filed April22, 1949 Jeda'y Q Nixon INVENTOR J. D. NIXON TUBING ANCHOR March 27,1951 2 Sheets-Sheet 2 Filed April 22, 1949 Patented Mar. 27, 1951 UNITEDSTATES PATENT OFFICE 6 Claims.

as well as making for less expensive manufacture by reducing the amountof machining and finishing required.

Another object of the invention is to provide an improved anchor havinga cylindrical body formed with elongate bosses and valleys between saidbosses, whereby the slips may be formed with inwardly directed wingsextending into thevalleys and holding the slips against circumferentialcreeping and more particularly, each wing giving sufflcient bulk orcross-sectional area to provide axial cores which are not reached whenthe slip is heat treated; such cores providing tough centers andenhancin the tensile strength and toughness of the slip.

' A construction designed to carry out the invention will be hereinafterdescribed together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawings,'wherein examples of the invention are shown, and wherein:

Fig. 1 is a view'partly in elevation and partly in section of a tubinganchor constructed in accordance with the invention,

Fig.2 is a horizontal cross-sectional view taken on the line 2-2 of Fig.1,

Fig. 3 is a vertical sectional view through one -of the slips,

Fig. 4 is an inner elevation of one of the slips,

Fig. 5 is a horizontal cross-sectional view taken on the line 5-5 ofFig. 4,

Fig. 6 is a plan view of one of the slips, and

Fig. 7 is a partial vertical sectional view of a modified form of theinvention.

In the drawings the numeral l0 designates a tubular insert or mandrelwhich ha a screwthreaded pin I l at its lower end and an internallyscrew threaded box 12 at its upper end, whereby it may be connected in astring of well tubing in the usual manner. At the medial portion of themandrel a cylindrical enlargement or body I3 is formed integraltherewith and connected at each end with the pin and box by annularshanks-0r necks I4;

2 At the top and bottom the body has annular, beveled seats [5 inclinedtoward the necks. At

the upper end of the pin an annular colla [6 is made integral with thelower neck l4. At the bottom of the box l2 an annular shoulder 11 isprovided. The distance between the upper seat I5 and the shoulder I! issubstantially the same as the distance from the bottom seat to thecollar 16. The necks with the collar and shoulder C011? stitute annulargrooves l8.

Quadrilateral, segmental slips or jaws I9 surround the body 53 and areof particular construe: tion. A description of one of the slips willsuifice for all of them. It will be observed that the body I3 is formedwith four equally spaced vertical bosses 20 having vertical valleys orrecesses 2T therebetween. The outer faces 22 of the bosses are curvedtransversely, preferably concentric to the outer faces of the slips.

Each slip I9 is formed with a transversely curved inner top and bottomsurfaces 23, substantially concentric to the necks M and with a verticalpocket or sump 24 receiving one of the bosses 29. The bottom 25 of thesump or inner face of the slip is struck on an are complementary to theface 22 of the boss so as to intimately engage said face, whereby aninward transverse thrust sustained by the slip is absorbed by the bossand distributed over the broad area of said boss.

The sump 24 is flared outwardly from its face 25 to conform to the seatsl5 and the sides of the boss. However, the sump is considerably largerso that when the faces 22 and 25 are in contact, no other portions ofthe'slip are intentionally in contact with any part of the body, exceptthat the slip may shift vertically and seat on one'of the seats IE or itmay shift circumferentially and'contact one side of the boss 22. Theinner surfaces 23 of the slip do not engage the necks l4.Thisconstruction provide for a free radial movement of the slip and asbefore stated, imparts its entire inward thrust to the face 22 of thess.-

The slip is formed with outer horizontal curvilinear teeth 26, as in-rnyformer Patent 1,941,813, these teeth are V-shaped in cross-section andbecause of their close spacing, as well as their shape, may be referredto as level threads. The teeth of the slip are disposed in such atransverse are that when all of the slips are fully expanded, they willbe in" an annulus substantially concentric to the casing or pipe, inwhich the anchor is located, so as to bite uniformly into the inner wallof said casing or pipe;

As is best shown in Figs. 2, 4 and 5, the slip vertical wings 2-1, theinner edges of which-are oifset outwardly from the top and bottomsurfaces 23 and extend into the valleys 2|. Each wing is flaredoutwardly or wedge-shaped in cross-section. It is preferable to dropforge the slip and to heat treat it to the required hardness. Since heattreating penetrates the surface of the metal, it will be seen thatbecause of the transverse or cross-sectional area of each wing,

sufficient body or bulk is provided, whereby a core or axial area isprovided in the center of the wings 2'! in providing a core inconnection with the heat treating of the slip.

the wing which is not hardened and this tough center enhances thetensile strength of the slip.

The Wings 21 not only increase the strength of the slip, but permits theouter surface of the slip to be turned down to fit a smaller diametercasing or pipe and the entire tooth surface to be heat treated. Thewings also hold the slip against undesired circumferential movement. Bydrop-forging the slip and its loose mounting on the boss 20, the onlymachining required is that of the teeth,

Each sliphas reduced integral segments 28 at its top and bottom aboveand below its teeth.

bore being spaced above the other bore and each bore having an annularstop shoulder or abutment 33 at its inner end surrounding an as anO-ring. It is obvious that when the inner .endsof the pistons'aresubjected to fluid :pressure, sufific'ient to overcome the spring rings39, said pistons will be forced outwardly, thereby displacing the Slipsl9 outwardly. 'When the fluid pressure is sufiiciently reduced. therings 30 will retract the slips and the pistons.

Anchors of this type are particularly adapted for use with reciprocatingwell pumps and be' cause of the V-shaped teeth, will hold the tubing andworking barrel against both upward and downward movement or creeping.The-anchor of course has many uses. By being able to turn down the slipsI9 to reduced diameters, the number of sizes in which the anchor must bemade is; reduced. The provisions of the wings,

whereby the web of. thebslip between said wings may be reduced inthickness, due to turning the face down to a reduced diameter withoutseriously weakening the slip, isquite angadvantage. I

\ ..In the prior patents hereinbefore referred to,

the slips were comparatively thin and of uniform thickness. .When suchslips were heat treated they had a tendency to become brittle and didnot lend themselves to machining to .reduce their diameters. Byemploying the wings the slips may be made thicker and the circumv ferential area which-contacts the bossesis less The foregoing descriptionof the invention is explanatory thereof and various changes in the size,shape and materialaas well as in the details of the illustratedconstruction may be made,

within the scope of the appended claims, without departing from thespirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A tubing anchor including, artubular mandrel adapted to be connectedin a well tubing and having a body intermediate its endsprovided withelongated bosses and valleys there- "oetween, radially movable slips onsaid bosses having thickened Wings disposed in the valleys, piston meansmounted in the bosses of the body exposed to the bore of the mandrel andengaging theslips, and retaining means holdingthe slips in assembledrelation to the body.

. 2.-A tubing anchor as set forth in claim 1, wherein'the bosses and theslips havecurvilinear contacting areas surrounding the piston meanbetweenthe valleys and wings.

3. A tubing anchor as set forth in claim 1, wherein the wings arewedge-shaped and each wing provides an axial unhardened core when the.slip is heat treated.

4. A tubing anchor including, a tubular man drel hELVll'lglYlBEtllSatseach endv for-connecting it in a string of well tubingan elongatebody intermediate the ends of. the mandrel having elongate bosses andelongate valleys betweensaid bosses, each boss having spacedcylindricalbores extendin radially therein and open to the bore of the mandrel,elongate cylindrical pistons fitting in the bores of the bosses and.surrounded by packing-rings, elongate slips having sumps receiving thebosses and the pistons, elongate wings on the slip on each side of thesumps extending into the valleys, and spring-rings surrounding the slipsand holding them on the bosses" 5. A tubing anchor as set forth in claim'4, wherein the outer faces of the bosses and bot,- toms of the slipsumps are concentric andin contact and said sumps, are larger than thebosses to provide freedom of movement of said slips.

6. A tubing anchor as set forth. in claim 1, wherein each boss has acircumferential groove and each slip has a transverse arcuate ribengaging in said groove. g

JEDDY D. NIXON.

7 REFERENCES CITED The following references are of record in'. the fileof this patent:

ST TES :eA'rErrrsv 1 UNITED 7,

Number Name a Date. .7 1,056,430 Wood Mar. 18,1913 1,713,150 Smith Ma14. 1929 1,912,805 Tilbury June 6,1933 1,941,813 I Nixon et a1. .Jan. 2,1934 1,972,408 Nixon Sept.,4, 1934 2,009,164 --Golmerauer July 23,1935

Gardner 4--.; July- .9; 1941

